Activists stormed a council meeting as part of a long-running feud over the removal of an unofficial shrine to murdered Fusilier Lee Rigby.
Greenwich Council angered "far right groups" by routinely taking items left at the spot where Fusilier Rigby died.
Police at Woolwich Town Hall intervened when onlookers shouted over a statement by council leader Denise Hyland.
A live feed of the meeting was stopped for 15 minutes as councillors left the room.
The council has said far-right groups used the shrine "for their own causes" and Fusilier Rigby's family supported its removal.
Protesters interrupted Ms Hyland as she said threats by a "scattering of people from the far right" would not be tolerated.
She was responding to death threats made to a council caretaker.
Earlier, a Met Police spokesman said the force was informed of a peaceful protest at the Town Hall in Woolwich, south-east London.
He said an undisclosed number of officers were stationed in the area to "keep an eye out".
An unofficial shrine had grown at the spot where Fusilier Rigby was murdered by extremists in May 2013.
But Greenwich Council said a plaque at St George's Garrison Church - opposite Woolwich Barracks, where he was stationed, and just 700m from where he was killed - is recognised by the family and the Army as the official local memorial.
Leader of the council, Denise Hyland, said Fusilier Rigby's family have told her "they absolutely do not want a memorial at the site of the murder".
She told BBC Radio London: "We are open to ways to publicly honour Lee Rigby, but putting a memorial at the site where he was cut down is not one of them."
The 25-year-old was off-duty when he was hit by a car outside the army barracks and then hacked to death.
A group called Wessex Resistance posted on its Facebook page that the council "refuse to put a plaque at the site of Lee Rigby's murder because they want to sweep it under the carpet".
The council said it is supported by multi-faith community representatives and would carry on removing items from the memorial every time new ones appeared.